Not quite sure about OP's and conquers. I don't believe they give you power. But the three major sources of power that you didn't mention come from
Relics (A lot from these)
Hope that helps!
crystals and relics only give score.
and army size is already mentioned
25 workers = 1 power
10 infantry = 1 power
10 vehicles = 2 power
10 tanks = 3 power
1 Alliance owned resource mine = 0.2 power for all alliance members. (Does stack)
these are the only sources of power. No OPs, conquers or structures give u power.